diff --git a/docs/others/observer.rst b/docs/others/observer.rst
index 62af03bf6a..d53eb9e631 100644
--- a/docs/others/observer.rst
+++ b/docs/others/observer.rst
@@ -122,7 +122,9 @@ Observer
 ********
 
 Subscribe to a subject
-----------------------
+----------------------ubject groups can be created. For the above example it looks like this:
+
+
 
 to subscribe to a subject the following function can be used:
 
@@ -176,50 +178,60 @@ To unsubscribe from a subject with all widgets you can use:
 Subject groups
 **************
 
-There are cases when a subject changes, the value of some other subjects are also required.
-As practical example imagine an instrument which measures either voltage or current.
+There are cases when a subject changes and the value of some other subjects are also required by the observer.
+As a practical example imagine an instrument which measures either voltage or current.
 To display the measured value on a label 3 things are required:
 
-1. What we measure (current or voltage)?
+1. What do we measure (current or voltage)?
 2. What is the measured value?
-3. What is the unit (mV, V, mA, A)?
+3. What is the range or unit (mV, V, mA, A)?
 
-What any of these 3 parameters changes the label needs to be updated,
+When any of these 3 parameters changes the label needs to be updated,
 and it needs to know all 3 parameters to compose its text.
 
-For these kind of scenarios subject groups can be created.
-For the above example it looks like this:
+To handle this you can create an array from some existing subjects and pass
+this array as a parameter when you initialize a subject with group type.
 
 .. code:: c
+    static lv_subject_t * subject_list[3] = {&subject_1, &subject_2, &subject_3}; 
+    lv_subject_init_group(&subject_all, subject_list, 3);  /*The last parameter is the number of elements*/
+
+You can add observers to subject groups in the regular way. 
+The trick is that when any element of the group is notified the subject group will be notified too. 
+
+The above Voltage/Current measurement example looks like this in the practice:
+
+.. code:: c
+
+    lv_obj_t * label = lv_label_create(lv_screen_active());
 
     lv_subject_t subject_mode;  //Voltage or Current
     lv_subject_t subject_value; //Measured value
     lv_subject_t subject_unit;  //The unit
     lv_subject_t subject_all;   //It will be the subject group
-    lv_subject_t subject_list[3] = {&subject_mode, &subject_value, &subject_unit};  //The elements of the group
+    lv_subject_t * subject_list[3] = {&subject_mode, &subject_value, &subject_unit};  //The elements of the group
 
     lv_subject_init_int(&subject_mode, 0); //Let's say 0 is Voltage, 1 is Current
     lv_subject_init_int(&subject_value, 0);
     lv_subject_init_pointer(&subject_unit, "V");
     lv_subject_init_group(&subject_all, subject_list, 3);
 
-    lv_subject_add_observer(&subject_all, all_observer_cb, some_label, NULL);
+    lv_subject_add_observer_obj(&subject_all, all_observer_cb, label, NULL);
 
     ...
 
-    static void some_observer_cb(lv_subject_t * subject, lv_observer_t * observer)
+    static void all_observer_cb(lv_subject_t * subject, lv_observer_t * observer)
     {
         lv_obj_t * label = lv_observer_get_target(observer);
-        lv_subject_t * subject_mode = lv_subject_get_group_element(subject, 0)
-        lv_subject_t * subject_value = lv_subject_get_group_element(subject, 1)
-        lv_subject_t * subject_unit = lv_subject_get_group_element(subject, 2)
+        lv_subject_t * subject_mode = lv_subject_get_group_element(subject, 0);
+        lv_subject_t * subject_value = lv_subject_get_group_element(subject, 1);
+        lv_subject_t * subject_unit = lv_subject_get_group_element(subject, 2);
 
         int32_t mode = lv_subject_get_int(subject_mode);
         int32_t value = lv_subject_get_int(subject_value);
         const char * unit = lv_subject_get_pointer(subject_unit);
 
-
-        lv_label_set_text_fmt(label, "%s: %d %s, mode ? "Current" : "Voltage", value, unit);
+        lv_label_set_text_fmt(label, "%s: %d %s", mode ? "Current" : "Voltage", value, unit);
     }